Flat cables are of structure in which plural conductive wires arranged on the same plane are put between two insulating tapes. Since such flat cables are flat and have bending ability, there are merits that it is easy to carry out wiring work and/or wiring can be made also at narrow portion, etc. For this reason, flat cables are widely used for internal wiring, etc. of various home electric products (equipments), communication equipments, word processors, computers and automotive vehicles.
Meanwhile, in manufacturing such flat cable, there is used a manufacturing apparatus as shown in FIG. 1, for example. In this manufacturing apparatus, plural conductive wires 1 arranged in parallel on the same plane are put between first insulating tape 2 and second insulating tape 3 while drawing them into portion between a pair of heating rolls 4 along with the first and second insulating tapes to heat and pressure-fit the first and second insulating tapes 2 and 3 by the pair of beating rolls 4.
At the first and second insulating tapes 2 and 3, adhesive or bonding layers are respectively formed on principal surfaces of the sides opposite to each other. Further, in this manufacturing apparatus, prior to delivering or sending the first and second insulating tapes 2 and 3 into the portion between the pair of heating rolls 4, first peeling or separation sheets 5 are continuously stuck with a predetermined sticking interval A on the adhesive layers of the first insulating tape 2 and second peeling sheets 6 are continuously stuck with a predetermined sticking interval B on the adhesive layers of the second insulating tape 3. When the first and second insulating tapes 2 and 3 are passed through a pair of heating rolls 4 so that they are pressure-fitted, the first and second peeling sheets 5 and 6 are opposed to each other.
Moreover, the first and second peeling sheets 5 and 6 are stuck in a manner respectively perpendicular to length direction of the first and second insulating tapes 2 and 3, and are stuck so that portions are respectively protruded from one ends in the width direction of the first and second insulating tapes 2 and 3.
In addition, in this manufacturing apparatus, cut portions are respectively formed along the outer shapes of the first peeling sheet 5 and the second peeling sheet 6 by means of press cutter (not shown) at the first and second insulating tapes 2 and 3. Thus, after the first and second insulating tapes 2 and 3 are heated and pressure-fitted, respective portions of the first and second insulating tapes 2 and 3 can be peeled off together with the first and second peeling sheets 5 and 6.
Accordingly, the conductive wires 1 are exposed towards the external from peeled off portions of the first and second insulating tapes 2 and 3. Further, the conductive wires 1 are cut off at the exposed portions. There is thus manufactured flat cable in which plural conductive wires 1 are coated with the first and second insulating tapes 2 and 3 and the conductive wires 1 are exposed from the both end portions.
Meanwhile, in manufacturing such flat cable, as shown in FIG. 2, it is required that first peeling sheet 5 stuck (attached) on the first insulating tape 2 and the second peeling sheet 6 stuck (attached) on the second insulating tape 3 are precisely opposite to each other when they are passed through the portion between a pair of heating rolls 4.
For this reason, in the manufacturing apparatus, as shown in FIG. 1, first tape roll 7a for supplying first insulating tape 2 and second tape roll 7b for supplying the second insulating tape 3 are disposed at positions respectively equal in distance from the pair of heating rolls 4. In addition, in this manufacturing apparatus, first sticking machine 8a for sticking first peeling sheets 5 and second sticking machine 8b for sticking second peeling sheets 6 are disposed at positions respectively equal in distance from the pair of heating rolls 4, and timings for sticking these first and second peeling sheets 5 and 6 are synchronized.
However, in such conventional manufacturing apparatus, e.g., in such cases of intermittent sending out for sending out in succession first and second insulating tapes 2 and 3, tensions applied to the first and second insulating tapes 2 and 3 are slightly changed (fluctuated) at the time of start of sending out or at the time of stop. For this reason, in the conventional manufacturing apparatus, there were instances where, as shown in FIG. 3, expansions/contractions of the first and second insulating tapes 2 and 3 change, whereby the first and second peeling sheets 5 and 6 are not precisely opposed to each other so that positional shift may take place.
Further, in the conventional manufacturing apparatus, when the first insulating tape 2 and the second insulating tape 3 are heated and pressure-fitted by a pair of heating rolls 4, adhesive layers formed on the first and second insulating tape 2 and 3 are thermally contracted. For this reason, in the conventional manufacturing apparatus, there might take place error in length of sticking (attachment) interval A of first peeling sheets 5 disposed with a predetermined interval and sticking (attachment) interval B of second peeling sheets 6 disposed with a predetermined interval.
As stated above, in the conventional manufacturing apparatuses, it was difficult to precisely oppose the first peeling sheet 5 and the second peeling sheet 6 for various causes. For this reason, with the conventional manufacturing apparatuses, there was the problem that it is difficult to manufacture high quality flat cables.
In addition, in the conventional manufacturing apparatus, in the case where such sticking (attachment) error takes place in the first and second peeling sheets 5 and 6, it was necessary for correcting such sticking error to once stop the apparatus and adjust it. However, the fact that the apparatus is allowed to be stopped results in cause to lower productivity to much degree.